/*
 * libusb example program to measure Atmel SAM3U isochronous performance
 * Copyright (C) 2012 Harald Welte <laforge@gnumonks.org>
 *
 * Copied with the author's permission under LGPL-2.1 from
 * http://git.gnumonks.org/cgi-bin/gitweb.cgi?p=sam3u-tests.git;a=blob;f=usb-benchmark-project/host/benchmark.c;h=74959f7ee88f1597286cd435f312a8ff52c56b7e
 *
 * An Atmel SAM3U test firmware is also available in the above repository.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <signal.h>

#include <libusb.h>

#define EP_DATA_IN    0x82
#define EP_ISO_IN    0x86

static int do_exit = 0;
static struct libusb_device_handle *devh = NULL;

static unsigned long num_bytes = 0, num_xfer = 0;
static struct timeval tv_start;

static void LIBUSB_CALL cb_xfr(struct libusb_transfer *xfr)
{
    unsigned int i;

    if (xfr->status != LIBUSB_TRANSFER_COMPLETED) {
        fprintf(stderr, "transfer status %d\n", xfr->status);
        libusb_free_transfer(xfr);
        exit(3);
    }

    if (xfr->type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS) {
        for (i = 0; i < xfr->num_iso_packets; i++) {
            struct libusb_iso_packet_descriptor *pack = &xfr->iso_packet_desc[i];

            if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
                fprintf(stderr, "Error: pack %u status %d\n", i, pack->status);
                exit(5);
            }

            printf("pack%u length:%u, actual_length:%u\n", i, pack->length, pack->actual_length);
        }
    }

    printf("length:%u, actual_length:%u\n", xfr->length, xfr->actual_length);
    for (i = 0; i < xfr->actual_length; i++) {
        printf("%02x", xfr->buffer[i]);
        if (i % 16)
            printf("\n");
        else if (i % 8)
            printf("  ");
        else
            printf(" ");
    }
    num_bytes += xfr->actual_length;
    num_xfer++;

    if (libusb_submit_transfer(xfr) < 0) {
        fprintf(stderr, "error re-submitting URB\n");
        exit(1);
    }
}

static int benchmark_in(uint8_t ep)
{
    static uint8_t buf[2048];
    static struct libusb_transfer *xfr;
    int num_iso_pack = 0;

    if (ep == EP_ISO_IN)
        num_iso_pack = 16;

    xfr = libusb_alloc_transfer(num_iso_pack);
    if (!xfr)
        return -ENOMEM;

    if (ep == EP_ISO_IN) {
        libusb_fill_iso_transfer(xfr, devh, ep, buf,
                sizeof(buf), num_iso_pack, cb_xfr, NULL, 0);
        libusb_set_iso_packet_lengths(xfr, sizeof(buf)/num_iso_pack);
    } else
        libusb_fill_bulk_transfer(xfr, devh, ep, buf,
                sizeof(buf), cb_xfr, NULL, 0);

    gettimeofday(&tv_start, NULL);

    /* NOTE: To reach maximum possible performance the program must
     * submit *multiple* transfers here, not just one.
     *
     * When only one transfer is submitted there is a gap in the bus
     * schedule from when the transfer completes until a new transfer
     * is submitted by the callback. This causes some jitter for
     * isochronous transfers and loss of throughput for bulk transfers.
     *
     * This is avoided by queueing multiple transfers in advance, so
     * that the host controller is always kept busy, and will schedule
     * more transfers on the bus while the callback is running for
     * transfers which have completed on the bus.
     */

    return libusb_submit_transfer(xfr);
}

static void measure(void)
{
    struct timeval tv_stop;
    unsigned int diff_msec;

    gettimeofday(&tv_stop, NULL);

    diff_msec = (tv_stop.tv_sec - tv_start.tv_sec)*1000;
    diff_msec += (tv_stop.tv_usec - tv_start.tv_usec)/1000;

    printf("%lu transfers (total %lu bytes) in %u miliseconds => %lu bytes/sec\n",
        num_xfer, num_bytes, diff_msec, (num_bytes*1000)/diff_msec);
}

static void sig_hdlr(int signum)
{
    switch (signum) {
    case SIGINT:
        measure();
        do_exit = 1;
        break;
    }
}

int main(int argc, char **argv)
{
    int rc;
    struct sigaction sigact;

    sigact.sa_handler = sig_hdlr;
    sigemptyset(&sigact.sa_mask);
    sigact.sa_flags = 0;
    sigaction(SIGINT, &sigact, NULL);

    rc = libusb_init(NULL);
    if (rc < 0) {
        fprintf(stderr, "Error initializing libusb: %s\n", libusb_error_name(rc));
        exit(1);
    }

    devh = libusb_open_device_with_vid_pid(NULL, 0x16c0, 0x0763);
    if (!devh) {
        fprintf(stderr, "Error finding USB device\n");
        goto out;
    }

    rc = libusb_claim_interface(devh, 2);
    if (rc < 0) {
        fprintf(stderr, "Error claiming interface: %s\n", libusb_error_name(rc));
        goto out;
    }

    benchmark_in(EP_ISO_IN);

    while (!do_exit) {
        rc = libusb_handle_events(NULL);
        if (rc != LIBUSB_SUCCESS)
            break;
    }

    /* Measurement has already been done by the signal handler. */

    libusb_release_interface(devh, 0);
out:
    if (devh)
        libusb_close(devh);
    libusb_exit(NULL);
    return rc;
}

